Reading Rabbi Salanter article "The Study of G-d-fearing and Mussar", Yirah is translated as fear, e.g. "The fear of G-d is the forces of all man's interactions between him and G-d.". Is the translation of yirah as fear the translator's choice or did Rabbi Salanter mean fear rather then awe or fear/awe?
To actually translate, I would say it's that feeling of enormity that both fear and awe have in common.
As for the Ramchal's three types of yir'ah, I believe he places fear of punishment outside the actual middah. That yir'ah means an awareness of G-d's Enormity and Significance, which comes in two aspects (corresponding to Caution and Alacrity) -- fear of wronging Him, and awe of His Infinity.
Rabbi Micha Berger

Three yirah's to consider
Michael,
Thanks for the question. This is a good one to get an expert to reply to, so I will try to find a good person to respond.
In the meantime, in Mesilat Yesharim (Path of the Just), there are three levels of Yirah discussed. The first is yirat ha-onesh - fear of punishment. The second is yirat he-romemut, fear of the exalted, which really is more awe of the exalted. And the third is yirat ha-chayt - fear of sinning.
Putting these into better language, the first is a baseline, somewhat childish yet natural response. I'm not going to do this bad thing for fear of being caught and punished. The second level is more about securing the relationship you have with G-d. If G-d is in relationship with you and right in front of you and you are faced with doing something that would damage that relationship, then if you looked up and saw G-d there, how would you feel? Likely in awe of the greatness of G-d and that would be enough to stop you in your tracks. The third level is again connected to the relationship you have with G-d. If doing something that took you away from a strong connection was placed in front of you as a temptation, would you do it? Not if you want to maintain the connection. So there is a fear of losing the connection through an act that takes you away. A sin is a chayt in Hebrew which is not so much a sin as we say in English, but more a deviation from the path of connection with G-d.
Those are the three levels of yirah that Rabbi Moshe Chayim Luzzatto speaks of.
Hopefully more to come.
Modya
Yirah
Shalom Modya,
Would you elaborate in a common fear -fear of loosing face, of making the wrong chice, of being critiziced. I can see its relationship to Humility, Faith, and other middot but I am interested in your thoughts about it. Thanks.
B'Simchah,
Leon
Fear as 'pakhad'
I think that the kind of fear you are asking about is not yirah, but pakhad (פחד). Yirah is a enabling fear/awe. Pakhad is a disabling, paralyzing fear.
I'm no psychologist ... but
Leon,
I see that fear as a ego-based fear and not the type of yirah that we're talking about here. I've heard it said that that type of fear is associated with doubt, meaning that it's really not about whether you live in a G-d-centred world, but rather it's self-centred and you fear that you may not make the grade.
Perhaps a question to ask when you feel the fear is "where is G-d in this situation". If the answer is that the fear you are experiencing about wrong choices, loosing face etc. is that you fear not serving G-d in the way that G-d would want you to, then it's yirah. If it's more about you looking bad, then it's not yirah.
My thoughts.
Modya